Topiramate may decrease the amount of estrogen in the body in women taking oral contraceptives, possibly increasing the chances of unwanted pregnancy.

Patients with seizure disorders taking anticonvulsant medications, including topiramate, may develop nerve toxicity from a chemical, 4'-O-methylpyridoxine, found as a contaminant in some ginkgo preparations.

PREGNANCY: Topiramate has been associated with abnormalities of the fetus (teratogenicity) in experimental animal studies. No data on fetal effects of topiramate exists in humans.

NURSING MOTHERS: Topiramate is excreted in the milk of lactating rats. It is not known whether topiramate is excreted in human milk or if it has important effects on nursing infants.

SIDE EFFECTS: In adults, the most common side effects of topiramate are tiredness, dizziness, coordination problems, speech problems, changes in vision or double vision, difficulty with memory, and sensory distortion.

In children, the most common side effects are drowsiness, tiredness, loss of appetite, nervousness, difficulty with concentration/attention, weight decrease, aggressive reaction and difficulty with memory.

Since topiramate was approved, there have been 23 cases reported (as of 8-17-01) of a sudden onset of vision and eye problems. Symptoms have typically occurred within the first month of therapy, with patients reporting an acute onset of decreased vision and/or eye pain. Eye examination revealed myopia (nearsightedness), redness, decreased depth of the anterior chamber of the eye and elevated ocular pressure, with or without dilation of the pupils. Fluid accumulation within the eye may displace the lens and iris anteriorly causing secondary angle closure glaucoma. If patients develop this syndrome, the treatment is to discontinue topiramate as rapidly as possible, according to the judgment of the treating physician.

Antiepileptic medications have been associated with increased risk of suicidal thinking and behavior. Anyone considering the use of antiepileptic drugs must balance this risk of suicide with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidal thoughts, or unusual changes in behavior.

Reference: FDA Prescribing Information